Method for using an MRI compatible biopsy device with detachable probe

ABSTRACT

A method for performing Magnetic Resonance Imaging (MRI) guided core biopsies is tendered more accurate and efficient by precisely positioning a disengaged probe assembly with respect to a localization fixture attached to a breast coil platform. The precise position is defined by MRI stereotopic location of suspicious tissue with respect to a fiducial marker on the localization fixture. With the probe inserted, dual lumens in the probe assembly are used for drainage or insertion of fluids as well as inserting diagnostic and therapeutic tools. Core biopsies are performed by engaging a biopsy instrument handle containing a cutter, with the localization fixture providing support and position to the handle. Repeated MRI scans are facilitated by the ability to disengage the handle without risk of displacing the probe assembly from the biopsy site.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application hereby claims the benefit of the provisionalpatent application of the same title, Ser. No. 60/374,807 filed on Apr.23, 2002. The present application is related to co-pending andcommonly-owned applications filed on even date herewith entitled“LOCALIZATION MECHANISM FOR AN MRI COMPATIBLE BIOPSY DEVICE” to Hibneret al. and “AN MRI COMPATIBLE BIOPSY DEVICE WITH DETACHABLE PROBE” toHibner et al., the disclosure of both is hereby incorporated byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates, in general to a method of imagingassisted tissue sampling and, more particularly, to an improved methodfor positioning a biopsy probe with respect to a magnetic resonanceimaging (MRI) breast coil for acquiring subcutaneous biopsies and forremoving lesions.

BACKGROUND OF THE INVENTION

The diagnosis and treatment of patients with cancerous tumors,pre-malignant conditions, and other disorders has long been an area ofintense investigation. Non-invasive methods for examining tissue arepalpation, Thermography, PET, SPECT, Nuclear imaging, X-ray, MRI, CT.and ultrasound imaging. When the physician suspects that tissue maycontain cancerous cells, a biopsy may be done either in an openprocedure or in a percutaneous procedure. For an open procedure, ascalpel is used by the surgeon to create a large incision in the tissuein order to provide direct viewing and access to the tissue mass ofinterest. Removal of the entire mass (excisional biopsy) or a part ofthe mass (incisional biopsy) is done. For a percutaneous biopsy, aneedle-like instrument is used through a very small incision to accessthe tissue mass of interest and to obtain a tissue sample for a laterexamination and analysis. The advantages of the percutaneous method ascompared to the open method are significant: less recovery time for thepatient, less pain, less surgical time, lower cost, less risk of injuryto adjacent bodily tissues such as nerves, and less disfigurement of thepatient's anatomy. Use of the percutaneous method in combination withartificial imaging devices such as X-ray and ultrasound has resulted inhighly reliable diagnoses and treatments.

Generally there are two ways to percutaneously obtain a portion oftissue from within the body, by aspiration or by core sampling.Aspiration of the tissue through a fine needle requires the tissue to befragmented into small enough pieces to be withdrawn in a fluid medium.The method is less intrusive than other known sampling techniques, butone can only examine cells in the liquid (cytology) and not the cellsand structure (pathology). In core sampling, a core or fragment oftissue is obtained for histologic examination, genetic tests, which maybe done via a frozen or paraffin section. The type of biopsy useddepends mainly on various factors present in the patient, and no singleprocedure is ideal for all cases. However, core biopsies seem to be morewidely used by physicians.

Recently, core biopsy devices have been combined with imaging technologyto better target the lesion. A number of these devices have beencommercialized. One such commercially available product is marketedunder the trademark name MAMMOTOME™, Ethicon Endo-Surgery, Inc. Anembodiment of such a device is described in U.S. Pat. No. 5,526,822issued to Burbank, et al., on Jun. 18, 1996, and is hereby incorporatedherein by reference.

As seen from that reference, the instrument is a type of image-guided,percutaneous, coring, breast biopsy instrument. It is vacuum-assisted,and some of the steps for retrieving the tissue samples have beenautomated. The physician uses this device to capture “actively” (usingthe vacuum) the tissue prior to severing it from the body. This allowsthe sampling of tissues of varying hardness. The device can also be usedto collect multiple samples in numerous positions about its longitudinalaxis, and without removing the device from the body. These featuresallow for substantial sampling of large lesions and complete removal ofsmall ones.

Co-pending application Ser. No. 09/825,899filed on Apr. 2, 1997, whichis hereby incorporated herein by reference, described other features andpotential improvements to the device including a molded tissue cassettehousing permitting the handling and viewing of multiple tissue sampleswithout physical contact by the instrument operator. Another describedtherein is the interconnection of the housing to the piercing needleusing a thumbwheel, to permit the needle to rotate relative to thehousing, while preventing the vacuum tube from wrapping about thehousing. During use, the thumbwheel is rotated so that the devicerotates within the lesion, and samples can be taken at different pointswithin the lesion.

In actual clinical use for breast biopsy the instrument (probe anddriver assembly) is mounted to the three axis-positioning head of anx-ray imaging machine. The three axis-positioning head is located in thearea between the x-ray source and the image plate. The x-ray machinesare outfitted with a computerized system which requires two x-ray imagesof the breast be taken with the x-ray source at two different positionsin order for the computer to calculate x, y and z axis location of thesuspect abnormality. In order to take the stereo x-ray images the x-raysource must be conveniently movable. The x-ray source therefore istypically mounted to an arm which, at the end opposite the x-ray source,is pivotally mounted to the frame of the machine in the region of theimage plate.

Recently, there has been a need for a hand held core sampling biopsydevice. This need has been fulfilled by Ethicon-Endo Surgery in U.S.Pat. No. 6,086,544 issued on Jul. 11, 2000, which is hereby incorporatedherein by reference. This aforementioned patent discloses a hand-heldMAMMOTOME™ that may be held approximately parallel to the chest wall ofthe patient for obtaining tissue portions close to the chest wall andmay be manipulated by the operator's hand. Thus, the operator may steerthe tip of the handpiece on the MAMMOTOME™ with great freedom towardsthe tissue mass of interest. The surgeon has tactile feedback whiledoing so and can thus ascertains to a significant degree, the densityand hardness of the tissue being encountered. In addition, a hand-heldMAMMOTOME™ is desirable because the handpiece on the MAMMOTOME™ may beheld approximately parallel to the chest wall of the patient forobtaining tissue portions closer to the chest wall than may be obtainedwhen using an instrument that is mounted to an electromechanical arm.

Recently, there has been a desire to use the above described biopsydevices with MRI imaging devices instead of x-ray imaging devices.However, existing medical biopsy sampling devices use small, multi-lumenprobes extensively fabricated mostly if not entirely from metal.However, the ability to provide accurate minimally invasive diagnosis ofsuspicious breast lesions hinges on the size of the sample obtained andaccuracy in placement of the sampling device.

The metallic nature of these probes has many drawbacks. Typically thesemetal probes are electrically conductive and often magnetically weak,which interferes with their use under MRI guidance. The electricallyconductive and magnetically weak nature of metal probes often work tocreate field distortions, called artifacts, on the image. The image ofthe lesion will show the metal probe, and this is problematic becausethe image of the probe can obscure the image of the lesion.

The small sample size of conventional biopsy needles also presents asignificant limitation due to the increase in the duration of theprocedure. Due to the tendency for contrast agent to “wash out” ofsuspicious lesions, and the progressive increase in enhancement ofsurrounding non-malignant breast parenchyma, suspicious lesions maybecome indistinguishable to the breast parenchyma within a few minutes.This limits the number of samples that can be retrieved usingconventional spring-loaded core biopsy needles under direct imagingguidance.

A further problem not infrequently encountered during core needle biopsyis the development of a hematoma at the biopsy site during theprocedure. An accumulating hematoma can be problematic during MRI-guidedbiopsy because residual contrast agent circulating in the hematoma canmimic enhancement in a suspicious lesion. In addition, the accumulationof air at the biopsy site can cause susceptibility artifacts that canpotentially interfere with the fat-suppression MRI techniques at thebiopsy site cavity.

These limitations of conventional biopsy needles have led severalauthors to conclude that lesions should be at least 1 cm in diameterbefore imaging could confirm that the MRI-guided biopsy device wasdefinitely within (as opposed to adjacent to) the suspicious target.However, the demand for minimally invasive MRI-guided core biopsy isgreatest for small lesions because they are more common, more difficultto characterize on MRI grounds alone, and have the best prognosis ifthey are found to be malignant.

Therefore, there has been a desire to have generally non-metallic(especially non-ferromagnetic) biopsy probe of the type described aboveto eliminate artifacts. These needs have been filled by co-pending andcommonly-owned application Ser. No. 10/021,680, “AN MRI COMPATIBLESURGICAL BIOPSY DEVICE” to Huitema et al filed on Dec. 12, 2001, thedisclosure of which is hereby incorporated by reference in its entirety.The lack of undesirable artifacts for the disclosed hand-held biopsydevice allows the accurate placement of the probe. Moreover, disclosedvacuum assist allows visualization of the lesion entering a bowl of theprobe to confirm accurate placement, as well as avoiding problemsassociated with a hematoma or an air cavity. Moreover, the volume andability to rapidly rotate the open cutting bowl of the probe allows formultiple samples in succession without removal of the probe. Thereby,the duration of the procedure is reduced.

However, elimination of the artifact created by the metal probe entirelyis also problematic because physicians rely extensively on some type ofartifact to notify them as to where the tip of the probe is relative tothe lesion. These needs have been filled by co-pending andcommonly-owned application Ser. No. 10/021,407, entitled “AN MRICOMPATIBLE BIOPSY DEVICE HAVING A TIP WHICH LEAVES AN ARTIFACT” to Rhadet al., filed on Dec. 12, 2001, the disclosure of which is herebyincorporated by reference in their entirety. Having a target in thecutter at the distal end of the probe helps avoid advancing the probethrough the chest cavity as well as accurately placing the bowl of theprobe adjacent to the suspicious tissue for drawing into the cuttingbowl.

While the aforementioned hand-held MRI compatible biopsy devices providemany advantages, opportunities exist for improvements and additionalclinical functionality. For instance, the hand-held biopsy devicepresents a long, external handle that is inappropriate for closed magnetMRI machines. Furthermore, while the hand-held biopsy device allowsgreat freedom in lateral and angular orientation, in some instances itis preferable to specifically position the biopsy probe. The MRI machinemay provide very accurate stereotactic placement information that isonly partially utilized in inserting the probe. In particular, thehand-held biopsy device is inserted through an opening in a compressionplate, so some two-dimensional alignment is provided. However, the angleand depth of insertion the probe tends to vary, especially withoutcontinual reimaging of the probe during insertion, which is particularlyinappropriate for closed MRI magnets.

Furthermore, the vacuum assist reduces occurrence of a hematoma anddraws in tissue to increase the sample size without repositioning theprobe; however, current clinical procedures often require additionalinvasive procedures to the biopsy site to administer anesthesia or toperform additional diagnostic or treatment procedures.

Consequently, a significant need exists for a method of performingMRI-guided biopsy that is applicable to both open and closed MRImachines, especially a method that allows a range of diagnostic andtherapeutic operations at the biopsy site with a minimum of invasiveprocedures.

BRIEF SUMMARY OF THE INVENTION

The invention overcomes the above-noted and other deficiencies of theprior art by providing a method whereby a core biopsy is accurately andefficiently performed even with only intermittent Magnetic ResonanceImaging (MRI) scans. The stereotopically derived coordinates of thesuspicious tissue are used by a surgeon to position alignmentpositioning guides on a localization mechanism that guide a core biopsytool. Thereby, even closed MRI machines may be used since constantmonitoring of the position of the core biopsy tool during insertion byMRI guidance is not required.

In one aspect of the invention, a method of MRI guided core biopsy ofsuspicious breast tissue of a patient's breast includes localizing thepatient's breast in the localization fixture, attaching a probe assemblyto the probe assembly guide, positioning the probe assembly guide for adesired spatial coordinate, inserting the probe assembly using the probeassembly guide to a desired biopsy site, and engaging a biopsyinstrument handle to the probe assembly. The biopsy instrument handleincludes a cutter that translates within the probe assembly to performthe core biopsy.

In another aspect of the invention, a method of MRI guided core biopsyof suspicious breast tissue is enhanced with a fiducial marker that iscoupled to the localization mechanism. Thereby, stereotopic coordinatesfor suspicious tissue are readily and accurately made with respect tothe localization mechanism. Since the localization mechanism alsopositions and guides the core biopsy tool, increased accuracy isachievable.

In yet another aspect of the invention, a method of diagnostic imagingguided biopsy includes positioning a probe at a specified spatialcoordinate on a compression plate of a localization fixture, therebyaccurately specifying the insertion point for the probe. Thereafterconstraining movement of the probe along an insertion angle for aspecified distance to the desired biopsy location. Maintaining theinsertion angle avoids the need to active image the probe duringinsertion to avoid an error due to the angle of insertion of under orover travel during insertion.

These and other objects and advantages of the present invention shall bemade apparent from the accompanying drawings and the descriptionthereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is plan view of the biopsy instrument, mounting fixture, anMagnetic Resonance Imaging (MRI) breast coil fixture, and patientsupport table in working relationship outside the confines of an MRImachine.

FIG. 2 is a plan view of the biopsy instrument, localization fixture,partially cut away MRI breast coil fixture, patient support table, andin working relationship and configured for insertion into a MRI machine.

FIG. 3 is a plan view of the localization fixture, partially cut awayMRI breast coil fixture, patient support table, and a detached probeassembly of the biopsy instrument mounted to the localization fixture,in working relationship and configured for insertion into the MRImachine.

FIG. 4 is an isometric view of the biopsy instrument disassembled into abiopsy instrument handle, probe housing, and probe.

FIG. 4A is a frontal isometric detail view of an alternative needle tipof a biopsy instrument.

FIG. 5 is an exploded isometric view of the biopsy instrument handle.

FIG. 6 is an exploded isometric view of the probe of the biopsyinstrument of FIG. 4.

FIG. 7 is a transverse cross section of the probe of the biopsyinstrument of FIG. 4 along lines 7-7.

FIG. 8 is an enlarged isometric view of the interface between the handleand probe housing illustrating the visual confirmation elements thatindicate the position of the distal end of the cutter.

FIG. 9 is a fragmentary plan view in partial section of the distalportion of the handle and probe housing and assembly, illustrating thedisconnect feature with the cutter retracted.

FIG. 10 is a fragmentary plan view in partial section of the distalportion of the handle and probe housing and assembly, illustrating thetolerance take-out feature and the disabled disconnect feature when thecutter is advanced.

FIG. 11 is an isometric view of the biopsy instrument with the handleportion disconnected from a tower/bracket localization fixture and probeassembly.

FIG. 12 is an isometric view of the biopsy instrument mounted to thetower/bracket localization fixture of FIG. 11.

FIG. 13 is an exploded isometric view of the tower/bracket localizationversion of the localization fixture and probe assembly of the biopsyinstrument.

FIG. 14 is a side elevation view of the biopsy instrument in partialsection to illustrate a tower/bracket support for stabilizing the handleand probe assembly of the biopsy instrument.

FIG. 15 is a side elevation view of the dual tower support version ofthe localization fixture positioning a detachable probe assembly withits dual lumens closed by a vacuum conduit and an obturator stylet.

FIG. 16 is an isometric view of the biopsy instrument mounted to a dualtower localization fixture.

FIG. 17 is an isometric view of the slide plate of a localizationfixture guiding a scissors support in a lowered position for verticallyorienting a biopsy instrument.

FIG. 18 is an isometric view of the slide plate of a localizationfixture guiding the scissors support in a raised position for verticallyorienting a biopsy instrument.

FIG. 19 is a sequence of clinical operations for using the detachableMRI-guided biopsy instrument of FIG. 1 in both open and closed MRImachines.

FIG. 20 is an isometric view of a tip protector mounted onto a needletip of the detachable probe assembly of FIG. 11.

FIG. 21 is an isometric detail view of the trip protector of FIG. 20.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 depicts a core biopsy instrument system 10 that is vacuumassisted, detachable, and compatible with use in a Magnetic ResonanceImaging (MRI) machine, such as the depicted closed MRI machine 12. Inthe illustrative embodiment, the core biopsy instrument system 10includes an MRI-compatible biopsy tool 14 that is selectably attached toa localization mechanism or fixture 16 to accurately and rapidly performcore biopsies of breast tissue with a minimum of insertions of a biopsyprobe. A control module (not shown) senses encoder position signal andswitch signals from the biopsy tool 14 and provides mechanical andvacuum power to the biopsy tool 14 via power cord 18.

With reference to FIGS. 1-2, a patient 20 is lying prone upon a patientsupport table 22, depicted in FIG. 1 as removed from a magnet bore 24 ofthe MRI machine 12. The patient's chest rests upon a top surface 26 of achest support 28, the top surface 26 having openings 30, 32 for allowingthe patient's breasts to hang downward for imaging and treatment. Withparticular reference to FIG. 2, the right opening 30 is depicted withthe localizer fixture 16 laterally positioned to cooperate with a medialcompression plate (not shown) to longitudinally fix and compress thepatient's right breast. Antenna elements (not shown) are placed aboutthe opening 30 to detect radio frequency (RF) signals emanated frombreast tissue induced by a strong magnetic field from the MRI bore 24.The chest support 28, localization fixture 16, and antennas are,collectively, generally termed a breast coil 34.

The biopsy tool 14 includes a biopsy handle 36 that is attachable to aprobe assembly 38. The localization fixture 16 accurately positions theprobe assembly 38 for stereotactic mammography biopsy procedures for aspecific biopsy site location for a distal tip 40 of the probe assembly38. This location is identified by an X-axis coordinate that ishorizontal and longitudinal with respect to the patient (up and down inFIGS. 2 and 3). A Z-axis is defined as the vertical height, with the Xand Z axis orthogonally defined on a lateral compression plate 42 of thelocalization fixture 16, the lateral compression plate 42 cooperatingwith the medial compression plate (not shown) to fix and compress thepatient's breast. This location is also defined in terms of depth ofinsertion, or Y-axis, which is horizontal and transverse with respect tothe patient (right to left in FIGS. 2 and 3). A probe assembly mountingdevice 150 connects to a probe housing 46 of the biopsy tool 14.

The mounting device 150 includes alignment positioning guides (describedin more detail below) to orient the probe housing 46, and hence theprobe assembly 38, to the desired X-Y-Z coordinate. For instance, adepth slide 48 allows mounting of the probe assembly 38 with the distaltip 40 extending outside of the opening 30 and lateral compression plate42. Thereafter, the probe assembly 38 is guided along the Y-axis by thedepth slide 48 while maintaining the selected X-Z-axes coordinates. Inaddition, the mounting device 150 advantageously supports the biopsyhandle 36 when attached to the probe assembly 38 as depicted in FIG. 2to maintain the angle of insertion of the probe assembly 38. The probehousing 46 provides access to the interior of the probe assembly 38 viaa vacuum lumen access conduit 50 for draining fluids, inserting fluidssuch as anesthetics.

FIG. 3 depicts the core biopsy instrument system 10 with the biopsyhandle 36 removed and the depth slide 48 moved inward to allow insertionof the patient support table 22 into the narrow confines of the MRImagnet bore 24. Moreover, the surgeon may take full advantage of thestereotactic coordinates provided by the MRI machine 12, even if using aclosed magnetic bore 24. In particular, the stereotactic derivedcoordinates may be used even if not actively imaging the probe assembly38 during insertion. The localization fixture 16 enables the surgeon tomanually insert the probe assembly 38 in depth with an indication ofcurrent depth. The surgeon is given tactile feedback while doing so andcan thus ascertain to a significant degree the density and hardness oftissue being encountered. In addition, with the probe assembly 38maintained in the correct location after insertion, the probe assembly38 provides access for other diagnostic and therapeutic tools and fluidtreatments.

Alternatively or in addition, a depth adjustment mechanism may beincorporated into the localization fixture 16 to provide mechanicaladvantage, thereby achieving a controlled and deliberate insertion ofthe probe assembly 38. Moreover, the depth adjustment mechanism mayincorporate a frictional, ratcheting or locking feature to preventinadvertent movement of the probe assembly 38 after placement at thedesired biopsy location. Examples of such depth adjustment include butare not limited to a thumb wheel in geared communication between theprobe assembly mounting device 150 and the localizer support frame 126.

FIG. 4 depicts the biopsy tool 14 with the biopsy handle 36 depicted asreadily attached to the probe housing 46, which in turn is readilyattached to the probe assembly 38. The probe assembly 38 includes a malecylindrical mating portion 52 presenting a central cutter opening 54 ona proximal end that is aligned with the longitudinal length of a cutterlumen 56 of an elongated needle 58. The cutter lumen 56 communicateswith a sample port 60 laterally presented near a needle tip 62 at thedistal end of the needle 58. The needle tip 62 is for penetrating thesoft tissue of a surgical patient. The needle tip 62 is sharpened and ispreferably made from an MRI compatible resin such as ULTEM or VECTRA. Inthe illustrative embodiment, the needle tip 62 is a three-sidedpyramidal shaped point, although the needle tip 62 configuration mayalso have other shapes and/or inserts. In addition, as in theaforementioned application Ser. No. 10/021,407, entitled “AN MRICOMPATIBLE BIOPSY DEVICE HAVING A TIP WHICH LEAVES AN ARTIFACT”, theillustrative embodiment advantageously includes a material that leaves asmall, but not troublesome artifact on an MRI scan.

Referring back to FIG. 4, it will be appreciated that a cutter elementor an obturator stylet is advanced inside the cutter lumen 56 to blockthe sample port 60 during insertion. Once the needle 58 is positioned,the sample port 60 is exposed to allow tissue to enter. In particular, avacuum may be presented to a “sample bowl” inside the cutter lumen 56near the sample port 60 by applying vacuum power through a vacuumchamber lumen 64 that communicates along the longitudinal length of theneedle 58 to the male cylindrical mating portion 52. In particular, aseries of small holes allow gas and fluid to enter the vacuum chamberlumen 64 from the sample port 60 but prevent tissue samples fromentering.

Annular rings 66 about the cylindrical mating portion 52 grip and sealto an interior of a female cylindrical mating portion 68 on the probehousing 46. Between annular rings 66, a proximal vacuum port (not shownin FIG. 4) communicates with a vacuum passage (not shown) in the probehousing 46. The engagement between the mating portions 52, 68advantageously allows rotation of the needle 58 with a thumb wheel 70annularly presented near the proximal end of the needle 58. The radialopening presented by the annular rings 66 maintains communicationbetween the vacuum passage in the probe housing 46 and the vacuumchamber lumen 64 regardless of radial orientation of the needle 58.Thereby, the sample port 60 may be presented to tissue at any and allradial positions about the distal end of the needle 58. With theassistance of vacuum, a large volume of tissue may be selectably drawninto the sample bowl for biopsy sampling.

The probe housing 46 includes laterally presented attachment prongs 72for mounting to the localization fixture 16. In addition, the probehousing 46 presents a proximally directed cuboidal engagement member 74with longitudinally aligned vertical and horizontal grooves 76 forflanges 78 from the biopsy handle 36. Referring to FIGS. 9 and 10, theprobe housing 46 also receives hooked locking tabs 80, 82 on the distalengaging end of the biopsy handle 36 for selective locking and unlockingunder the influence of a pair of opposing depression grips 84, 86attached to respective tabs 80, 82. The biopsy handle 36 includes asample window 88 for extracting any tissue sample withdrawn from thecutter lumen 52 under the influence of a vacuum passing through thecutter, as described in more detail below.

FIG. 5 depicts a disassembled biopsy handle 36 that contains the meansfor translating and rotating a cutter 90 within the cutter lumen 56. Itwill be appreciated that two rotating mechanical power sources arepresented to the proximal end of the biopsy handle 36 through the powercord 18 to provide the independent translation and rotation motions.These two rotating mechanical power sources enter through a cord opening92 defined between a removable shell 94 and a bottom shell 96, the twoheld together by screws. The removable shell 94 is removed whenassembling a power cord 18 to the handle 36. A lower gear housing 98 issupported upon the bottom shell 96 and cooperates with a top shell 100to constrain movement of an elongate drive screw 102, an elongate axialscrew 104 and cutter carriage 106. In particular, both screws 102, 104are allowed to rotate, positioned parallel to one another and thelongitudinal axis of the cutter lumen 56. Each screw 102, 104 is drivenby a respective power source from the power cord 18. The drive screw 102passes through the carriage 106 and interacts with corresponding ridgestherein to impart a longitudinal translation corresponding to thedirection and rate of rotation of the drive screw 102.

In some applications, a single rotary power source may be used as analternative to two independent rotating mechanical power sources. Atransmission mechanism at the biopsy handle 36 may convert the singlerotary power source into the two motions, translation and rotation. Asyet another alternative, the single rotary power source may directlysupply both a translation and rotary motion. Such a translating androtating power cable would be coupled to the cutter 90 to directlycontrol its movement.

The cutter 90 is an elongate tube with a sharpened distal end forcutting tissue presented within the distal end of the cutter lumen 56.The proximal end of the cutter 90 includes a cutter gear 108 that isexposed through a gear window 110 of the carriage 106 to mesh with theaxial screw 104 for axial rotation of the cutter 90. A tissue remover111 is a tube that is fixedly aligned with the longitudinal axis toenter the proximal end of the cutter 90. The tissue remover 111 extendsup to the sample window 88 and has a vacuum selectably applied to it bythe control module. Thus, when the cutter 90 is retracted, vacuum fromthe tissue remover 111 draws the sample to the distal end of the cutter90 for retraction to the sample window 88, whereupon the sampleencounters the tissue remover 111 and is dislodged for exiting thebiopsy tool 14.

The carriage 106 includes distally projected guides 112, 114 thatadvantageously take-out slack between biopsy handle 36 and the probehousing 46, as well as providing indicia to the surgeon as to the depthof translation of the cutter 90. Taking out slack between the assembledparts of the handle 36 and housing 46 advantageously minimizes thedeadzone length of the distal end of the needle 58. The cutter 90 shouldcompletely translate past the sample port 60 in order to reliably cut asample. To ensure a full cut, the cutter 90 should translate the maximumdistance expected for the assembly. If variation exists in manufacturingtolerances between the engagement components, then a further distancehas to be included in the cutter lumen 56 distal to the sample port 60to accommodate the over-travel. Thereby, the needle tip 62 must beadvanced farther than desirable in some instances, preventing placementof the sample port 60 near critical body tissues. At or near fulltravel, the guides 112, 114 contact the probe housing 46, causingmovement of the housing 46 to its maximum, distal position. Thus,critical dimensioning to minimize tolerance build-up is simplified.

FIG. 5 also depicts a brace 116 and brace arm 118 that are employed inone version of the localization fixture 16 to support the weight andmaintain the alignment of the handle 36. Thereby, flexure of theassembly is avoided that may place a load on the probe assembly 38, andthus unwanted movement of the needle 58 from the desired biopsy sitelocation.

FIGS. 6-7 depict the needle 58 of FIG. 4 and described more fully in theaforementioned application Ser. No. 10/021,680, entitled “AN MRICOMPATIBLE SURGICAL BIOPSY DEVICE”. In particular, elongated needle 58is formed from a left body member 120 and a right body member 121 oneither side of the longitudinal axis. The edges of the halves 120 and121 are gated for easy part filling, and the edges are stepped withridges that allow the two halves 120 and 121 to attach together withease. The two halves 120, 121 are adhesively attached to one another. Acutter tube liner 122 is inserted between the two halves 120, 121 toprovide a smooth surface for the cutter 90, especially by preventingadhesive from entering the cutter lumen 56 during assembly.

FIG. 8 shows an enlarged view of the engagement of the handle 36 to theprobe housing 46, with the advanced cutter 90 evident through the window88. In addition, the guides 112, 114 are advanced almost into contactwith the probe housing 46, indicating that the distal end of the cutter90 is approaching its furthest translation. The guides 112, 114 contactthe probe housing 46 when at or near this extreme to take-out anytolerance. Indicia on the side of the guides 112, 114 may be referencedby the surgeon to determine the position of the cutter. Also shown inmore detail is hooked locking tabs 80, 82 entering the probe housing 46,the thumb wheel 70 used to rotate the needle 58, and the vacuum lumenaccess conduit 50 used to evacuate or otherwise access the vacuum lumen64.

FIGS. 8-10 show that each grip 84, 86 includes a respective inwardlyprojecting member 124, 125 that contact the guides 112, 114 when thecutter 90 is distally advanced, thereby preventing removal of the handle36. In FIG. 9, the cutter 90 is retracted, allowed the depression of thegrips 84, 86, unlocking the hooked locking tabs 80, 82 from the probehousing 46. In FIG. 10, cutter carriage 106 is advanced, the guides 112,114 are contacting the probe housing 46, thereby removing anylongitudinal gap between the hooked locking tabs 80, 86 and the probehousing 46.

FIGS. 11-14 depicts a localization fixture 16 that includes means foraccurately positioning the probe assembly 38 and supporting the biopsyhandle 36. In particular, a localizer support frame 126 is formed fromthe compression plate 42 in a hinged, orthogonal relation to ahorizontal slide plate 128, both laterally attached to one another bygussets 130, 132. Rods 134, 136 horizontally pass through thecompression plate to adjustably attach to the medial compression plate(not shown) for compressing the patient's breast. Apertures, depicted asparallel rows of slots 138, in the compression plate 42 are provided toobtain access to a desired biopsy site location while providing enoughremaining structure in the compression plate 42 for adequate contactwith the patient's breast. Alternatively, the apertures may be a seriesof holes aligned both vertically and horizontally, parallel columns ofslots, or a large opening of other shapes. As yet a further alternative,portions of the compression plate 42 may be permeable to allow anaperture to be formed as needed.

The desired biopsy site location is stereotopically determined during anMRI scan with reference to a fiducial marker 140 that presents a smallartifact. The fiducial marker 140 is contained within a fiducial markerholder 142 that may be placed at a convenient location on thecompression plate 42, accurately placed with reference to indents spacedalong the slots 138. Alternatively, the fiducial marker may be embeddedor affixed to the compression plate 42.

The localizer support frame 126 defines and provides the guide forpositioning the probe assembly 38. The X-Y-Z axes are defined withregard to the slots 138 and compression plate 42. In particular, thevertical dimension, or Z-axis, and horizontal dimension, or X-axis, aredefined by the surface of the compression plate 42. The depth dimension,or Y-axis, is defined as distance away from the plane of the compressionplate 42. The horizontal slide plate 128 includes laterally alignedfront and back rails 144, 146 for setting the X-axis coordinate.Horizontal indicia 148 along the front rail 144 give the surgeon anaccurate measurement of the position of a probe assembly mounting device150.

A first version of the mounting device 150 is depicted that uses asingle vertical pedestal 152 to position and support the probe assembly38. In addition, the biopsy handle 36 is supported by a brace 116, whichis connected to the proximal underside of the handle 36 and to a handlesupport rod 156 that is slid through a rod hole 158 at the correspondingside of the vertical pedestal 152. The appropriate height for the brace116 is determined by selecting one of a range of slots arrayed along theunderside of the handle, thereby pivoting the brace 116 about a bracearm 118 whose first end slidably pivots within a slot 162 in the middleof the brace 116 and second end attaches to the distal end of the handle36.

With the handle 36 detached from the probe assembly 38 as depicted inFIG. 11, an obturator stylet 164 is slid into the cutter lumen 56 toclose the cutter port 88. The stylet 164 may have radially-orientedthrough holes near its distal end to maintain fluid communicationbetween the vacuum lumen chamber 64 and cutter lumen 56. Alternatively,the stylet 164 may be partially withdrawn, allowing the cutter port 88to be in fluid communication with the conduit 50.

A slide 166 includes a grooved underside to horizontally slide on rails144, 146 of the slide plate 128. The slide 166 also includes a centralchannel 168 oriented in the Y-axis depth dimension to guide the pedestal152 as it slides in the Y-axis direction. Sufficient range of motion indepth is achieved with a pivoting depth slide 170, aligned and pivotallyattached to the slide 166. With the pivoting depth slide 170 in itslowest, horizontal position, the pedestal 152 may be slid outwardsufficiently for the probe assembly 38 to be out of the compressionplate 42. With the pedestal 152 distally slid onto the slide 166, thepivoting depth slide 170 may be pivoted upward or otherwise removed.Depth indicia 172 along the central channel 168 give the surgeon anindication of the insertion depth of the probe assembly 38.

A vertical slide 174 slides on the pedestal 152 for vertical positioningalong the Z-axis, with a measurement provided by vertical indicia 176 onthe pedestal 152. Holes 178 on each lateral side of the vertical slide174 allow mounting of the probe housing 46 on either side by insertionof attachment probes 72.

FIGS. 15-16 depict a second version of the mounting device 150 that usesa second vertical pedestal 180 in lieu of a brace assembly to supportthe handle 36. The probe housing 46 is also depicted as attached to theopposite side of the first vertical pedestal 152. A second verticalslide 181 of the second vertical pedestal 180 contacts the firstvertical slide 174, as shown in FIG. 16, so that setting the verticalheight for both is accomplished in one step. Each vertical slide 174,181 moves in a ratchet fashion against its respective vertical pedestal152, 180, and thus remains in position after being separated from oneanother as shown in FIG. 15. Moreover, the close nesting of the twovertical pedestals 152, 180 enhances the ability to minimize theproximal displacement of the localization fixture 16 when used withinthe close confines of a closed MRI magnetic bore 24. It will be furtherappreciated that the second vertical slide 181 includes a shaped areathat engages the underside of the handle 36 in such a way as tocorrectly align the handle 36 at the same X-axis horizontal dimension asthe probe assembly 38.

FIGS. 17-18 depict a third version of the mounting device 150 whereinthe slide 166 and pedestal 152 are replaced with a scissors tableassembly 182 that includes a first slide 184 for horizontal movement ona slide plate 128 and a second slide 186 for vertical movement relativeto the slide plate 128. Similar to the slide 166 of FIGS. 11 and 13having the central channel 168, the second slide 186 of FIGS. 17-18 hasa top channel 188. With particular reference to FIG. 18, a pair ofscissors braces 190 are extended when drawn together with a screw 192,thereby elevating the second slide 186 with respect to the first slide184. It will be appreciated that the third version of the mountingdevice 150 advantageously provides a level support for both thedetachable probe assembly 38 as well as the biopsy handle 36 withouthaving to perform two vertical adjustments, as well as not having toperform two separate attachments for each of the handle 36 and probeassembly 38.

FIG. 19 depicts a sequence of operations, or method 200, for performingan MRI-guided breast core biopsy that accurately and quickly performs acore biopsy even in a closed MRI. Moreover, the method takes fulladvantage of the stereotopic location information rendered from the MRIscan to position an MRI compatible core biopsy probe without thenecessity of continuous imaging of the distal tip of the biopsy probe.

Prior to performing a clinical breast biopsy, the equipment isinitialized to ensure proper function. Thus, in block 202, the probethat comprises a needle, thumb wheel and housing is assembled with thehandle. The assembled biopsy tool is connected via a power cord to acontrol module and the system is powered up, initiating power up logicin the control module (block 204). Parameters for rotation speed andtranslation distances are loaded. If the control module determines thatthe system has not been powered up recently, such as 60 minutes, theninitialization logic is performed. Thus, translational drivetraininitialization is performed (block 206); rotational drivetraininitialization is performed (block 208); and vacuum systeminitialization is performed (block 210). If initialization is notrequired, then blocks 206-210 are bypassed.

Then, the patient's breast is immobilized in the localization mechanism(block 212) and the patient is moved into the MRI magnet bore (block214). An MRI scan is performed to stereotopically locate suspicioustissue with reference to a movable fiducial marker on the localizationmechanism (block 216). For a closed MRI magnet bore, the patient is thenremoved (block 218), which is not necessary for an open bore. Anesthesiais administered prior to the minimally invasive vacuum assisted corebiopsy procedure (block 220). Using the X-Y-Z positioning capabilitiesof the localization mechanism, the positioning guides on thelocalization mechanism are positioned for insertion to the predeterminedbiopsy site (block 222).

Optionally, insertion may be enhanced by use of an insertion toolinstalled through the probe assembly 38 (block 224). For instance, anultrasonic cutting tip, extender, and outer tube assembly may beinserted through the probe assembly 38 through a slot in the needle tip62, or exiting from the sample port 60 to be snapped onto the needle tip62. This could be accomplished with a housing on the ultrasonic devicethat is configured to snap onto the needle 58, similarly to how a trocarobturator snaps onto the trocar cannula. Then, the ultrasonic tip isenergized prior to insertion into the patient.

The probe assembly is mounted on the localization mechanism (block 226)at the designated X-Z coordinate and with the mounting device withdrawnalong the depth axis. The cutter lumen is sealed with an obturatorstylet (block 228), if not otherwise sealed by a tool in block 224. Thevacuum lumen may be similarly sealed (e.g., stopcock attached to vacuumlumen access conduit 50) or be used to aspirate fluid and tissue duringinsertion. Then the probe is advanced along the Y-axis, guided by thelocalization mechanism to avoid misalignment (block 230). Once in place,if an insertion enhancement tool was installed in block 224, then thistool is withdrawn through the cutter lumen of the probe assembly (block232).

With the probe in place, various fluid transfers may advantageously takeplace through the probe assembly (block 234). For example, vacuum may beapplied through the vacuum lumen with the sample port exposed to drainany hematoma or air bubble formed at the biopsy site. Treatment fluidsmay be inserted directly to the biopsy site, such as anesthesia or MRIcontrast agent. If the patient is to be scanned in a closed magnet bore,then the patient is moved back into the bore for scanning (block 236).In addition, vacuum may optionally be applied to the biopsy site to drawin suspicious tissue into the bowl of the sample port for confirmationprior to cutting the sample (block 238). Then, the MRI scan is performedto confirm placement of tissue in the bowl of the probe assembly, andadjustment of the probe assembly placement and re-scans are performed asrequired (block 240).

Sample mode is selected through the control module to perform thesequence of steps to translate and rotate the cutter according topredetermined settings, with vacuum assist to draw in the sample and toretract the sample along with the cutter to the sample window (block244). If more samples at this biopsy site are required for diagnostic orfor treatment purposes (block 246), then the thumb wheel is rotated toreorient the sample port to another angle (block 248), and sample modeis performed again by returning to block 244.

After the core biopsy is performed, the probe assembly provides anexcellent opportunity for other minimally invasive diagnostic proceduresand treatments without the necessity for another insertion. If thebiopsy handle is installed, such as in an open MRI magnet bore, thehandle is removed so that the detachable probe assembly may be accessed(block 250). Examples of tools that may be inserted through the probeassembly include: (1) gamma detectors; (2) energized tunneling tips toreduce tunneling forces; (3) inserts to aid in reconstruction of removedtissue (e.g., one or two sided shaver inserts); (4) spectroscopy imagingdevices; (5) general tissue characterization sensors {e.g., (a)mammography; (b) ultrasound, sonography, contrast agents, power Doppler;(c) PET and FDG ([Flourine-18]-2-deoxy-2-fluoro-glucose); (d) MRI orNMR, breast coil; (e) mechanical impedance or elastic modulus; (f)electrical impedance; (g) optical spectroscopy, raman spectroscopy,phase, polarization, wavelength/frequency, reflectance; (h)laser-induced fluorescence or auto-fluorescence; (i) radiationemission/detection, radioactive seed implantation; (j) flow cytometry;(k) genomics, PCR (polymerase chain reaction)-brca1, brca2; (l)proteomics, protein pathway}; (6) tissue marker sensing device; (7)inserts or devices for MRI enhancement; (8) biochips on-a-stick; (9)endoscope; (10) diagnostic pharmaceutical agents delivery devices; (11)therapeutic anti-cancer pharmaceutical agents delivery devices; (12)radiation therapy delivery devices, radiation seeds; (13) anti-seedingagents for therapeutic biopsies to block the release of growth factorsand/or cytokines (e.g., chlorpheniramine (CPA) is a protein that hasbeen found to reduce proliferation of seeded cancer sells by 75% in cellcultures.); (14) fluorescent tagged antibodies, and a couple fiberoptics to stimulate fluorescence from a laser source and to detectfluorescence signals for detecting remaining cancer cells; (15) positivepressure source to supply fluid to the cavity to aid with ultrasoundvisualization or to inflate the cavity to under the shape or to reducebleeding; (16) biological tagging delivery devices (e.g., (a) functionalimaging of cellular proliferation, neovacularity, mitochondrial density,glucose metabolism; (b) immunohistochemistry of estrogen receptor,her2neu; (c) genomics, PCR (polymerase chain reaction)-brca1, brca2; (d)proteomics, protein pathway); and (17) marking clips.

Then, a tissue marker is inserted through the probe assembly so thatsubsequent ultrasonic, X-ray, or MRI scans will identify the location ofthe previous biopsy (block 252) and the probe is removed (block 254).

FIGS. 20-21 depict a tip protector 260 that advantageously protects theneedle tip 62 of the probe assembly 38 prior to insertion into tissueand simplifies localization of the probe assembly 38 in some instances.Furthermore, the tip protector 260 does not interfere with pre-clinicalsetup procedures (e.g., testing for vacuum leaks). In particular, thetip protector 260 includes an attachment member 262 with clips onto theneedle 58 without obstructing the sample port 60. A distal portion ofthe tip protector completely encompasses the needle tip 62 with aprotection member, depicted as a hemispheric disk 264, that may beplaced in contact with a patient's breast without discomfort. Inaddition, in some applications the hemispheric disk 264 may be comprisedof or include an MRI artifact producing material, such as thosedescribed above. Since the hemispheric disk 264 is MRI scanned outsideof the patient's breast, a stronger artifact may be presented to aid inquickly locating the artifact without obscuring the suspected lesion.

With a novel fiducial marker integrated into the tip protector 260,there is potentially one less step in the localization process foroperators that prefer to position fiducial marker at the closestinsertion point to a suspected lesion prior to insertion. Procedurally,with the tip protector 260 in place, the operator would attach the probeassembly 38 onto the pedestal 152 and move the probe assembly 38 upagainst the breast tissue in the vicinity of where they believe thesuspicious tissue to be, based on an earlier diagnostic image. Next,when the distance from this fiducial marker to the lesion is calculated,the “delta” distances are based on where the probe is currentlypositioned. There is a fixed offset along the Y axis to account for thedistance from the fiducial to the middle of the bowl. The attachmentmember 262 accurately locates the hemispheric disk 264 so that thisY-axis offset is predictable. This would be more intuitive because thedelta positions are from where the probe is currently located.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art. For example, although thedetachable probe assembly provided numerous benefits, it will beappreciated aspects of the present invention may be directed to a singlepiece biopsy tool. For example, access to the cutter lumen fordiagnostic and therapeutic tools may be incorporated through the cutteror similar openings.

For another example, although a localization mechanism 16 is depictedthat laterally compresses a downward hanging patient's breast, aspectsof the present invention are applicable to other orientations oflocalization and imaging.

As an additional example, although MRI is discussed herein as theimaging modality for stereotopically guiding the core biopsy, aspects ofthe present invention apply to other imaging modalities.

As yet a further example, although a Cartesian X-Y-Z positioningapproach is disclosed herein, it will be appreciated that a polar orspherical positioning approach may be implemented in whole or in part sothat the detachable probe assembly enters at a predefined angle.

As yet an additional example, although a prone breast compression deviceis depicted, application of the present invention may be used in medicalcompression devices oriented in other manners, to include standing,lying on one side, or supine. In addition, aspects of the presentinvention may be applicable to positioning a biopsy probe through amedial compression plate, or a top and bottom compression plate pair,instead of a lateral compression plate. Furthermore, aspects of thepresent invention are applicable to other diagnostic imaging modalitiescurrently used or that become available in the future. In addition,aspects of the present invention would have application to diagnosticguided biopsy procedures on other portions of the body, as well as topositioning a probe for utilizing other diagnostic and treatment devicesin a minimally invasive manner.

As yet a further example, an elongate needle may be formed without astructural, longitudinal barrier between the vacuum chamber lumen andthe cutter lumen. Instead, the advancing cutter 90 may define a cutterlumen having a circular cross section within a noncircular cross section(e.g., oval) of the internal cavity of the elongate needle. Moreover, anoncircular liner may be used to prevent adhesive entering theundifferentiated internal cavity.

1. A method of performing a biopsy of tissue located at coordinates in afirst, second, and third dimension, the method comprising: (a)localizing a patient's breast in a localization fixture, wherein thelocalization fixture comprises: (i) a probe assembly comprising: aproximal end, a distal end, a lumen, an opening in communication withthe lumen, wherein the opening is positioned proximate to the distalend, and an insertion tool operable to selectively block the opening,(ii) a probe assembly guide coupled to the probe assembly, and (iii) acompression plate operable to stabilize the patient's breast, whereinthe compression plate comprises: elongate slots extending along thefirst dimension, wherein the slots are spaced apart along the seconddimension, wherein the act of localizing the patient's breast comprisescompressing at least a portion of the breast with the compression plate;(b) locating suspicious tissue with an MRI scan; (c) definingcoordinates in the first, second, and third dimensions that correspondto the location of the suspicious tissue; (d) inserting the probeassembly into the patient's breast guided by the probe assembly guide,wherein the probe assembly is inserted along the third dimension,wherein the probe assembly is inserted through one of the elongate slotsof the compression plate; (e) performing a selected one of a diagnosticprocedure, surgical procedure and a therapeutic procedure with the probeassembly inserted into tissue and detached from a biopsy instrument; (e)engaging a handle of the biopsy instrument to the proximal end of theprobe assembly, wherein the biopsy instrument comprises a cutter sizedto translate in the lumen of the probe assembly, wherein the cutter isretracted in the handle at the initiation of the act of coupling thehandle to the probe assembly; and (f) advancing the cutter through thelumen in the probe assembly to the tissue.
 2. The method of claim 1,wherein the probe assembly further comprises a needle, wherein theopening of the probe assembly comprises a cutter opening laterallypresented near the distal end of the probe assembly, the probe assemblyfurther comprising a vacuum lumen and a cutter lumen, wherein the cutterlumen is configured to receive the cutter of the biopsy instrument,wherein the vacuum lumen and cutter lumen are both in fluidcommunication between the proximal end of the probe assembly and thecutter opening of the probe assembly, the method further comprising:with the biopsy instrument engaged to the probe assembly, applyingvacuum through the biopsy instrument and through the lumens of the probeassembly.
 3. The method of claim 2, further comprising: sealing thecutter lumen with an obturator stylet that allows fluid communicationbetween the vacuum lumen and the cutter opening.
 4. The method of claim1, wherein performing the selected one of the diagnostic procedure,surgical procedure and the therapeutic procedure with the probe assemblyinserted into tissue and detached from a biopsy instrument furthercomprises with the biopsy instrument disengaged from the probe assembly,transferring fluid through the inserted probe assembly for a therapeutictreatment.
 5. The method of claim 1, wherein performing the selected oneof the diagnostic procedure, surgical procedure and the therapeuticprocedure with the probe assembly inserted into tissue and detached froma biopsy instrument further comprises inserting a tool through theproximal end of the probe assembly.
 6. The method of claim 1, whereinthe probe assembly includes a target operable to present an artifact toan MRL machine, the method further comprising: with the probe assemblyinserted into the tissue and the biopsy instrument disengaged,positioning the patient within a closed MRI machine bore and performingan MRI scan.
 7. The method of claim 1, further comprising: coupling afiducial marker to the localization fixture.
 8. The method of claim 1,further comprising: attaching a tip protector onto the probe assembly,the tip protector including a fiducial marker; attaching the probeassembly to the probe assembly guide; and positioning the probe assemblyguide for a desired spatial coordinate.
 9. The method of claim 1,further comprising: locating the probe assembly guide to a desiredinsertion point on the localization fixture; and using the probeassembly guide to insert the probe to a desired biopsy site at aconstrained angle.
 10. The method of claim 1, wherein performing theselected one of the diagnostic procedure, surgical procedure and atherapeutic procedure with the probe assembly inserted into tissue anddetached from a biopsy instrument comprises imaging the probe assemblyto confirm a location of an area of interest in the tissue relative tothe inserted probe assembly.
 11. A method of a diagnostic imaging guidedminimally invasive procedure, comprising: (a) localizing a human breastin a localization fixture; (b) stabilizing the human breast using acompression plate including a series of apertures, wherein the act ofstabilizing comprises compressing at least a portion of the breast withthe compression plate; (c) diagnostic imaging the human breast to locatea tissue location; (d) attaching a probe assembly to a probe guideassembly coupled to the localization fixture; (e) positioning the probeguide assembly to a lateral spatial location on the human breast; (f)guiding the probe guide assembly along horizontal and verticaldirections parallel to the lateral spatial location on the human breastto an insertion angle to position the probe assembly at the tissuelocation; (g) inserting the probe assembly into the human breast guidedby the probe guide assembly toward a medial side of the human breast,wherein the act of inserting the probe assembly further comprisesinserting the probe assembly through one of the apertures of thecompression plate; (h) engaging a handle including a cutter to the probeassembly to obtain a core biopsy sample through the probe assembly,wherein the cutter is fully retracted within the handle when the handleis initially engaged to the probe assembly, such that the cutter doesnot protrude from the handle when the handle is initially engaged to theprobe assembly; and (i) advancing the cutter relative to the handle andinto the probe assembly to sever a tissue sample.
 12. The method ofclaim 11, wherein guiding the probe assembly along the insertion anglefurther comprises: using a depth adjustment mechanism to gain mechanicaladvantage.
 13. The method of claim 11, wherein guiding the probeassembly along the insertion angle further comprises referring to depthposition indicia.
 14. The method of claim 11, wherein positioning theprobe assembly to a spatial location on the body portion furthercomprises: adjusting the probe guide assembly to a desired horizontalposition; and adjusting the probe guide assembly to a desired verticalposition.
 15. The method of claim 14 wherein adjusting the probe guideassembly to a desired horizontal and vertical position further comprisesreferring to horizontal and vertical position indicia.
 16. The method ofclaim 11, wherein the probe assembly includes a cutter lumen and avacuum lumen in fluid communication with the cutter lumen, and whereinthe act of advancing the cutter further comprises: inserting the cutterthrough the cutter lumen for severing a tissue sample; and drawing avacuum through the vacuum lumen to assist in drawing in the tissuesample into the cutter lumen.
 17. The method of claim 16, furthercomprising: transferring a fluid through the vacuum lumen to perform atherapeutic treatment to the tissue location.
 18. A method forperforming a biopsy, the method comprising: (a) localizing a bodyportion in a localization fixture, wherein the localization fixturecomprises: (i) a probe assembly comprising: a proximal end, a distalend, a cutter lumen, and an opening in communication with the cutterlumen, wherein the opening is positioned proximate to the distal end,(ii) a probe assembly guide coupled to the probe assembly, and (iii) acompression plate operable to stabilize the body portion, wherein thecompression plate comprises apertures arranged along first and seconddimensions, wherein the act of localizing comprises compressing at leasta portion of the body portion with the compression plate; (b) imagingthe body portion to determine a tissue location relative to thelocalization fixture; (c) determining the tissue location relative tothe localization fixture with respect to first, second, and thirddimensions; (d) positioning the probe assembly at the tissue locationrelative to the first and second dimensions guided by the probe assemblyguide; (e) inserting the probe assembly along the third dimension toplace the opening of the probe assembly proximate to the tissuelocation, wherein the act of inserting comprises inserting the probeassembly through one of the apertures of the compression plate; (f)imaging the body portion to determine the tissue location relative tothe inserted probe assembly; (g) coupling a handle of a biopsyinstrument to the probe assembly, wherein the biopsy instrumentcomprises a cutter configured to translate through the cutter lumen ofthe probe assembly, wherein the biopsy instrument is configured toselectively engage with the probe assembly, wherein the cutter isretracted within the handle at the initiation of the act of coupling thehandle to the probe assembly; (h) advancing the cutter of the biopsyinstrument through the cutter lumen of the probe assembly; and (i)severing a portion of tissue at the tissue location with the cutter,wherein the portion of tissue is severed adjacent the opening of theprobe assembly.
 19. The method of claim 18, wherein the opening of theprobe assembly is blocked during the act of inserting the probe assemblyinto the body portion, the method further comprising unblocking theopening of the probe assembly prior to advancing the cutter of thebiopsy instrument.
 20. The method of claim 18, the method furthercomprising substantially restraining movement of the probe assemblyguide along the first and second dimensions after the act of positioningthe probe guide assembly at the tissue location relative to the firstand second dimensions.
 21. The method of claim 18, the method furthercomprising substantially restraining movement of the probe assemblyalong the third dimension after the act of inserting the probe assemblyinto the body portion.
 22. The method of claim 18, wherein the biopsyinstrument comprises a drive mechanism operable to communicate linearand rotational movement to the cutter, wherein the act of advancing thecutter comprises communicating linear movement to the cutter with thedrive mechanism, and wherein the act of severing a portion of tissuecomprises communicating rotational movement to the cutter with the drivemechanism.
 23. The method of claim 18, wherein the biopsy instrumentfurther comprises a window, wherein the window is located proximate tothe proximal end of the probe assembly when the biopsy instrument iscoupled to the probe assembly, wherein the method further comprisesextracting the severed portion of tissue through the window.